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Letter
Methicillin-resistant Staphylococcus
aureus Skin Infections
To the Editor: Moran et al. write, "In areas with a high
prevalence of CA-MRSA [community acquired methicillin-resistant Staphylococcus
aureus], empiric treatment for skin and soft tissue infections (SSTIs)
with β-lactam agents such as cephalexin may no longer be appropriate.
Oral agents such as clindamycin or trimethoprim/sulfamethoxazole and rifampin
should be considered in CA-MRSA" (1). However,
some studies have had different results. Lee et al. reported that 31 (84%)
of 37 Texas children with CA-MRSA SSTIs showed clinical improvement after
incision and drainage, even though they received an "ineffective"
antimicrobial agent that was not changed after the susceptibility results
became available (2). These researchers also reviewed
some reports with similar experience in the United States and further
suggested that incision and drainage without adjunctive antimicrobial
therapy were effective in immunocompetent children for CA-MRSA SSTIs <5
cm in diameter.
Several studies on Taiwanese children with CA-MRSA SSTIs agree with the
viewpoint of Lee et al. Chen and colleagues reported that 22 (63%) of
35 episodes of CA-MRSA superficial soft tissue infections in children
were cured by nonsusceptible antimicrobial therapy, regardless of surgical
intervention (3). In a study by Wang et al., oxacillin,
with or without incision and drainage, was effective in 16 (89%) of 18
children with CA-MRSA SSTIs, even in a case with high-level oxacillin
resistance (MIC>8 μg/mL) (4). Fang et al.
also reported that 16 (55%) of 29 children with CA-MRSA SSTIs were eventually
cured with therapy to which their infections were not susceptible (5).
With these experiences and concerns about the growing problem of bacterial
resistance, we suggest that incision and drainage, with or without adjunctive
antimicrobial therapy, are adequate to treat noninvasive CA-MRSA SSTIs
in immunocompetent children and that oxacillin or first-generation cephalosporins
are still effective and sufficient under such conditions. Vancomycin and
other agents that are effective against MRSA isolates should be reserved
for invasive CA-MRSA infections or for immunocompromised patients. Although
Moran's study was focused on adults, not on children as these studies
were, we believe these suggestions are also appropriate when applied to
CA-MRSA SSTIs in adults.
Finally, the antibiogram of CA-MRSA isolates may vary from country to
country. In Taiwan, CA-MRSA isolates are also resistant to multiple antimicrobial
agents; 71.4%, 91.4%, and 41.2% are resistant to clindamycin, erythromycin,
and chloramphenicol, respectively (4). Trimethoprim/sulfamethoxazole
is more effective against CA-MRSA isolates than other first-line antimicrobial
agents: the resistance rate is 0%–65.7% (4,5). Therefore,
clindamycin and trimethoprim/sulfamethoxazole may be not adequate empiric
antimicrobial agents for SSTIs in Taiwan or other areas with a high prevalence
of CA-MRSA.
Jui-Shan Ma*
*Show-Chwan Memorial Hospital, Changhua, Taiwan
Suggested citation
for this article:
Ma J-S. Methicillin-resistant
Staphylococcus aureus skin infections [letter]. Emerg Infect Dis
[serial on the Internet]. 2005 Oct [date cited]. Available from
http://www.cdc.gov/ncidod/EID/vol11no10/05-0680_05-0858.htm
References
- Moran GJ, Amii RN, Abrahamian FM, Talan DA.
Methicillin-resistant Staphylococcus aureus in community-acquired
skin infections. Emerg Infect Dis. 2005;11:928–30.
- Lee MC, Rios AM, Aten MF, Mejias A, Cavuoti D, McCracken GH Jr, et
al. Management
and outcome of children with skin and soft tissue abscesses caused by
community-acquired methicillin-resistant Staphylococcus aureus.
Pediatr Infect Dis J. 2004;23:123–7.
- Chen CJ, Huang YC, Chiu CH, Su LH, Lin TY. Clinical
features and genotyping analysis of community-acquired methicillin-resistant
Staphylococcus aureus infections in Taiwanese children. Pediatr
Infect Dis J. 2005;24:40–5.
- Wang CC, Lo WT, Chu ML, Siu LK. Epidemiological
typing of community-acquired methicillin-resistant Staphylococcus
aureus isolates from children in Taiwan. Clin Infect Dis. 2004;39:481–7.
- Fang YH, Hsueh PR, Hu JJ, Lee PI, Chen JM, Lee CY, et al. Community-acquired
methicillin-resistant Staphylococcus aureus in children in northern
Taiwan. J Microbiol Immunol Infect. 2004;37:29–34.
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In response: Dr Ma makes an excellent point
about the limitations of study data on antimicrobial drug treatment of
skin abscesses (1). All of the patients described in
our study (2) required antimicrobial drug therapy, and
most were admitted to the hospital. However, we did not mean to imply
that all skin abscesses require antimicrobial drug treatment. Our own
practice is to give antimicrobial drug therapy only when a skin abscess
is associated with definite surrounding cellulitis, systemic signs, or
both. Although various criteria have been published, in practice this
is a judgment call, and we suspect that physicians vary considerably in
use of antimicrobial agents for skin infections.
Because most cellulitis associated with skin abscess will improve with
adequate drainage, designing a study that will find a difference in outcome
attributable to the antimicrobial drug is difficult. More studies are
needed to determine whether antimicrobial agents with in vitro activity
against methicillin-resistant Staphylococcus aureus (MRSA) are
more clinically effective than those lacking such activity. Perhaps these
studies should focus on those infections for which antimicrobial agents
would be expected to have the greatest impact (e.g., infected wounds with
cellulitis), rather than abscesses that can be expected to improve with
incision and drainage alone.
When the decision is made to use an antimicrobial agent, it is difficult
to justify choosing one to which the infecting organism will likely be
resistant. Because MRSA is now the most common cause of skin infections
at our institution, we choose agents with activity against the MRSA strains
in our community. We do not believe that choosing an antimicrobial agent
to which the infecting organism is susceptible is more likely to contribute
to the general problem of antimicrobial drug resistance.
Gregory J. Moran,*
Ricky N. Amii,* Frederick M. Abrahamian,* and David A. Talan*
*Olive View–UCLA
Medical Center, Sylmar, California, USA
Suggested citation
for this article:
Moran GJ, Amii RN,
Abrahamian FM, Talan DA. Methicillin-resistant Staphylococcus aureus
skin infections [response]. Emerg Infect Dis [serial on the Internet].
2005 Oct [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol11no10/05-0680_05-0858.htm
References
- Ma J-S Methicillin-resistant Staphylococcus aureus
skin infections [letter]. Emerg Infect Dis. 2005;11:1644–5.
- Moran GJ, Amii RN, Abrahamian FM, Talan DA. Methicillin-resistant
Staphylococcus aureus in community-acquired skin infections.
Emerg Infect Dis. 2005;11:928–30.
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